Patch from Catalin Marinas

The compiler allocates r14 for the stk variable in the __asm__ directive.
This is a shadowed register and gets changed when the mode is changed,
causing random values in the SP register. The patch adds a clobber for
the r14 register.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>